Trim-indicator for ships.



R. G. ROBERTS.

TRIM INDICATOR FOR SHIPS.

APPLICATION FILED SEPT. 10, 1913.

1,1 10,347, Patented Sept. 15, 1914.

fl 6 w D1 1) C B I B THE NORRIS PETERS co FHOTO-LITHO.. WASHINGTON D. C.

' solid platform or framing on the ship.

UNrrEn srawnnrormon RICHARD GADWALADB nosnnrs, o'r'wY'ME-sWoLn, ENGLAND.

TRIM-INDICATOR FOR; SHIPS;

To all whom it may concern:

Be it known that I, RICHARD CADWALADR ROBERTS, a subject of the King of Great Britain, and a resident of VVymeswold, Leioestershire, in England, have invented a certain new and useful Improved Trim-Indicator for Ships, of which the following is a specification.

This invention relates to improvements in trim indicators for ships of the kind in which a pendulum or the like is suspended in or on a frame, and means are provided forexactly indicating theposition of the former relatively to the latter.

Referring to the drawings, Figure l. is a perspective view of a trim indicator constructed according to my invention, showing the tilting 'mirror removed. Fig. 2. is a perspective view of themain framing of the indicator, and Fig. '3. a vertical section showing the tilting mirror in positionv Like letters indicate like parts throughout the drawings.

According to this invention, the main part of the indicator consists of a skeleton frame A, provided at the base with leveling screws B which may also serve to secure it go a uspended within this frame is a lever C. D. (see Fig. 1.) the main dependent member 0 of which is provided at its lower end with a heavy weight or bob E. The lever described is provided with two suspension heads G which are situated some distance apart and are adapted to rest on horizontal knife edge fulcrums F (see Fig. 2.) secured to the respective sides of the upper part of the main frame A, so that said lever can swing freely in a vertical plane. The other member D of the weighted lever described, extends approximately in a horizontal direction, and its free end D is carried up through an opening G in the upper part of the main framing A, and terminates in a plane surface which is approximately horizontal and level with the upper surface of the said frame A, when the lever is at zero.

In the construction shown in the drawings, the upper end of the main member C of the weighted lever G D is divided, and the member D is formed by branches from the said divided upper end of C, and a single branch from its lower end all united at the free end D providing a lever construction Specification of Lettersl'atentf Patented Sept. 15, 1914.

Application filed September 10, 1913. Serial No. 789,105

which is not materially deflected by strains or changes in temperature. As the weighted lever C. D will owing to the action of gravity, always maintain the same position in space, any movement of the main frame A relatively thereto will be indicated by'a movement of the free end D of the-member D relatively to the upper surface of. said frame, and this is indicated to an amplified extent on a fixed scale on the framing,

by an optical system arranged as follows An approximately vertical mirror H (see Fig. 3.) is carried on a base J provided with say three legsJ J and this 'mirror H is placed with two of its legs J resting on the upper surface of the framing A, and the remaining leg J resting on the plane sur face at the free end D of the member D of the lever O. D. Any movement of the latter relatively to the, main frame A thus serves to tilt the mirror H either one way or the other. To prevent displacement of the mirror H, the lower ends of thelegs J J are pointed, and small recesses M (see Figfl.) are provided for them in the upper surface of the framing A, and the free end D of the lever C D respectively.

On the frame A opposite to themirror H, is a vertical scale K (see Fig. 1.) and at the side of the scale is a telescope L fitted with a cross wire. The several parts are so disposed that an image of the scale K is seen in the mirror H by looking through the telescope L, and the position of the cross wire in the latter as seen in relation to the scale, is determined by the inclination of the mirror H, which arrangement indicates to a very much amplified extent, any movement of the weighted lever C D relatively to the frame A. I

In use the indicator is placed on a firm platform or framing in any convenient part of the ship, and it is set so that the weighted lever C D moves in a direction which is exactly fore and aft of the vessel. It is then when the ship is trim, leveled carefully by the screws provided for this purpose until the cross wire in the telescope registers with zero in the middle of the scale K. This leveling may be done once and for all on a favorable occasion when it is known that the ship is exactly trim. At any subsequent time, the trim of the ship can be obtained by simply taking the reading from the scale K and multiplying that reading by a factor which is peculiar to and constant for that particular ship, and is supplied with the instrument. 1

The advantages of the instrument are many, it is compact, strong, works automatically, and it is not liable to get out of order. The great magnification of the primary motion which is obtained by using a tilting mirror, telescope, and scale, is not obtained at the expense of accuracy, as the amplification is obtained by the reflection of light,

and not by the multiplication of moving parts. Its immense sensitiveness is exemplified in the fact that a scale division which will indicate an inclination of one in six thousand can be easily read.

What I claim as my invention and desire to cover by Letters Patent is 1. In a trim indicator, the combination, with a frame adapted to partake of the motion of the ship, of a lever pivotally supported by the frame, a weight which holds the lever relatively stationary in the frame, and an oscillatory indicating mirror pivotally supported between the said lever and frame.

2. In a trim indicator for ships, the combination of a framing, a weighted lever suspended in or on said frame, and optical in dicator mechanism with a mirror which is connected to and tilted by a movement of the lever relatively to the frame, substantially as described.

3. In a trim indicator for ships, the combination of a framing, a weighted lever suspended in or on said frame, a fixed scale, and optical indicator mechanism consisting of a telescope with a cross wire, and a mirror which is connected to and tilted by a movement of the lever relatively to the frame, substantially as described.

4. In a trim indicator for ships, the combination of a framing, a weighted lever suspended in or on said frame, a mirror which is supported on the frame and the free end of one member of said lever respectively so that it is tilted by a movement of the latter relatively to the frame, a fixed scale, and a telescope with a cross wire, substantially as described.

5. In a trim indicator for ships, the combination of a framing, a weighted lever suspended in said framing, a mirror connected to and tilted by said lever, a fixed scale, and

a telescope with cross wire, said scale and telescope being so disposed that an imagev of the scale can be seen in the mirror on looking through the telescope and the position of the cross wire on said image be observed, substantially as described.

6. In a trim indicator for ships, the combination of a framing, a weighted lever suspended on knife edges in said framing, a mirror supported partly by the frame and Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents,

Washington, I). C. 

